P677: CLINICAL EFFICACY AND TOLERABILITY OF VENETOCLAX PLUS RITUXIMAB IN RELAPSED OR REFRACTORY CHRONIC LYMPHOCYTIC LEUKEMIA – REAL WORLD ANALYSIS OF POLISH ADULT LEUKEMIA STUDY GROUP
Authors: A. Soboń, J. Drozd-Sokołowska, E. Paszkiewicz-Kozik, L. Popławska, M. Morawska, J. Tryc-Szponder, L. Bołkun, J. Rybka, K. Pruszczyk, A. Juda, A. Majeranowski, E. Iskierka-Jażdżewska, P. Steckiewicz, K. Wdowiak, B. Budziszewska, K. Jamroziak, I. Hus, E. Lech-Marańda, B. Puła
Journal: HemaSphere (2022)

Background: The introduction of venetoclax into clinical practice has improved the outcome of patients with relapsed/refractory chronic lymphocytic leukemia (RR-CLL). The results of the MURANO trial published in March 2018 showed significantly longer progression-free survival (PFS) and overall survival (OS) in RR-CLL patients treated with venetoclax and rituximab (VEN-R) comparing to bendamustine and rituximab (BR) and resulted in the approval of VEN-R in the therapy of RR-CLL in the European Union and the United States. It should be noted that the results of registration studies often do not correspond with the data from real-life observations. Aims: To study the clinical efficacy and safety profile of VEN-R treatment in RR-CLL patients outside clinical trials. Methods: We performed retrospective analysis of RR-CLL patients treated with VEN-R in hematology centers of the Polish Adult Leukemia Study Group (PALG) from 2019 to 2021. Results: Clinical data of 117 RR-CLL patients treated with VEN-R were collected. Median patient age upon initiation of VEN-R therapy was 67 years (range 33 – 84 years). Seventy-two patients (61.5%) were men. Median Cumulative Illness Rating Scale (CIRS) was 6 (range 2 - 16). Patients were treated with a median of 2 (range 1–9) previous lines of therapy, whereas 32 patients (27.4%) had relapsed following the first line of treatment. Overall, 25 patients (21.4%) had 17p deletion, whereas TP53 mutation was identified in 13 patients (11.1%). The median follow-up was 9.96 months (range 0.27 - 29.13). The overall response rate (ORR) was 95.2%. Seventeen patients (14.5%) achieved complete remission (CR), 83 (70.9%) partial remission (PR), while in 5 patients (4.3%) disease progression was noted. In the patients with 17p deletion (n=22) or TP53 mutation (n=11), CR and PR were observed in 4 (12.1%) and 29 (87.9%) patients, respectively. The median PFS in the whole cohort was 20.8 (95% CI 18.43 - not reached) months and the median OS was not reached. In our study none of the analyzed clinico-pathological factors had significant impact on ORR, PFS and OS. During the follow-up time four (3.4%) cases of Richter transformation were diagnosed. There were 18 deaths recorded during the course of observation; 3 (16.7%) due to disease progression and 7 (38.9%) due to COVID-19 infection. The others were due to infections other than SARS-CoV-2 (n=3, 16.7%) and the cause of death could not be specified in five cases (27.8%). Eighty-three patients (70.9%) remain on treatment, while treatment was discontinued in thirty-four cases (29.1%). Reasons for therapy discontinuation included patient’s death (52.9%), treatment-related cytopenias (17.6%), disease progression (14.7%), Richter’s transformation (11.8%), autoimmune hemolytic anemia (5.9%), diarrhea (2.9%) and infections (8.8%). In one case treatment discontinuation was due to consent withdrawal and one patient was lost to follow-up. The following adverse events of VEN-R treatment were reported during the study: all grade neutropenia (71.8% with grade 3/4 in 55.6%), anemia (51.3%), thrombocytopenia (47%), pneumonia (9.4%), neutropenic fever (6.8%), autoimmune hemolytic anemia (4.3%), immune thrombocytopenic purpura (1.7%), diarrhea (4.3%) and in one case exacerbation of heart failure was observed. Summary/Conclusion: In this retrospective analysis the outcomes of treatment with the VEN-R regimen in real-life setting were worse than those reported in the MURANO trial.